Skip site navigation (1)Skip section navigation (2)
Date:      Sun, 15 Feb 1998 21:39:57 +0000 (GMT)
From:      Terry Lambert <tlambert@primenet.com>
To:        roberto@keltia.freenix.fr (Ollivier Robert)
Cc:        hackers@FreeBSD.ORG
Subject:   Re: VM messed: vm_page_free panic problem
Message-ID:  <199802152139.OAA03239@usr01.primenet.com>
In-Reply-To: <19980215132713.12891@keltia.freenix.fr> from "Ollivier Robert" at Feb 15, 98 01:27:13 pm

next in thread | previous in thread | raw e-mail | index | archive | help
> > Are you mounting async?
> 
> Yes but the panic happens at *boot* time when the kernel just finished to
> probe. No FS is mounted async at that moment.

If an FS was mounted async, it could have been damaged beyond the
ability of fsck to repair it as the result of a crash.  I do not
spend time railing against async just because I like to hear myself
type.  I do it because async is actually dangerous to FS integrity.

*If* you had a file, and *if* the pages in that file were crosslinked
to another file, and *if* both files had been faulted in, and *if*
one had been freed, *then* when you went to free the second, you
would be "freeing free page" off the devvp.

Actually, the reason I asked about what the VM object was (which you
can only get by running a kernel debugger against the dump) was
to see whether or not this was a buffer on a mount device, a buffer
on a swap device, or a buffer on a vnode being used as a swap store.


> > Are you trying to use union mounts, or any other FS other than FFS,
> > such as NFS, MSDOSFS, etc.?
> 
> No.

OK, this rules out the worst of the minefield.


> > Have you compiled your kernel -g, then copied it, "strip -d"'ed the
> > copy, and run on the stripped copy until you got a panic, so you could
> > do a source level debug of the kernel code in question?
> 
> This was a 3.0-SNAP boot floppy :-)

Ah.  Compression.  Disable your internal and external cache for the
time you are booting, and see if it fixes it.  Also, do you have 48M?
If so, remove 16M for the install.

Do you have a 3.0 installed?  You should take the kernel from the
SNAP and see if you can boot it normally, or if the floppy itself
is corrupted (ie: try another floppy, try the kernel not on the floppy,
etc.).

You should be able to boot a 3.x kernel on a 2.x system, so long as
you don't go multiuser (multiuser requires the new mount, new net
code, etc.).


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199802152139.OAA03239>